This invention relates to a balustrade of a passenger conveyor such as an escalator, a moving sidewalk, and so on, and more particularly to a balustrade of a passenger conveyor, which balustrade has a simplified construction.
A passenger conveyor has held an important position as indispensable transportation equipment inside a building and its use has been widespread up to this date. However, extremely diversified needs exist at present for the passenger conveyor, such as reduced power consumption, improved safety, a design having a side transparent portion, and so forth.
The construction of a typical passenger conveyor comprises a main body frame supported by the floor of a building, balustrades supported by the main body frame, handrails, and steps arranged and circulated endlessly in synchronism with the handrails.
One of conventional balustrades comprises glass panels supported by the main body frame, a handrail frame unit supported by the glass panel through the packing for protecting the glass panel, and a guide secured to the handrail frame unit to guide the handrails. The handrail frame unit holds illumination appliances at the outside of the glass panel so that the handrail frame unit is much wider in width than the handrail and projects a little both into the inside, that is, the passenger side and into the outside beyond the side faces of the handrail, about 10 mm and 50 mm, respectively.
This conventional passenger conveyor balustrade has several problems to be solved with respect to safty and design.
From the aspect of safety, it may happen that children can not completely grip the handrail. Namely, the height of the handrail from the steps is set to be from 650 to 750 mm to prevent the fall of passengers, and this height is suitable for the passengers above the school age. In the case of the children, however, a part of the hand comes into contact with the corner projecting inside the handrail frame as a problem besides the problem of height, and they can not easily grip the handrail. If a child attempts to grip the handrail under such an unstable state, the child's legs approach the skirt guard and will sometimes be caught around the steps. This is extremely dangerous.
From the aspect of design, there is the problem that the powder produced by abrasion of the handrail is piled on the handrail frame. This powder is a mixture of the powder produced by the abrasion. lost is due to friction of iron and rubber materials used for the driving system of the handrail and a material of the canvas portion. The feel of dirtiness and possible pollution of the clothes of passengers by this powder can not be neglected in the handrail equipment as public transportation facilities.
Further, demands are increasing recently for the balustrade having a wide transparency design and reduced power consumption without the illumination appliances.
When the illumination appliances are to be removed, it is a customary practice to cover the inside of the handrail frame with closing plate but not to change the members for the handrail frame. In the passenger conveyor without the illumination applicances, the intensity of illumination of the ceiling illumination is generally increased to insure sufficient service for passengers in order particularly to make the step portion sufficiently bright. From the aspect of lighting, however, the dimensions and construction of the conventional balustrade are extremely disadvantageous.
When the brightness of the ceiling illumination is to be introduced to the steps through the glass panel, the projecting dimension and the height of the handrail frame restrict the angle of the incidence of the rays of light. This state is particularly serious when the surroundings of the passenger conveyor are covered with a screen or the like, and the intensity of illumination indispensable for the safty of passengers can not be secured from time to time.
U.S. Pat. No. 3,989,133 and Japanese Laid-open Publication No. 108482/1976 can be cited as example of prior art. In these prior art, in which a guide frame with a U-shaped recess is mounted on the upper edge portion of a glass panel through a flexible groove-shaped member, some of the above-mentioned problems are solved, but some are still left unsolved. For example, a lower half of the guide frame is exposed outside from the handrail, so that the exposed guide frame shortens the transparent portion of the glass panel. It is necessary that the groove-shaped member should always apply a relatively large force to the guide member and the glass panel. Even a little deformation of leg portions of the guide member loosens the fastening of the guide frame and the glass panel, therefore, the leg portions need be thick. The groove-shaped member is necessary to keep such a force for a long time without being weakened.
U.S. patent application, Ser. No. 406,787 filed on Aug. 10, 1983, also discloses a balustrade improved on safety and design as above-mentioned. The balustrade comprises a glass panel and a guide frame mounted on the glass panel for guiding the handrail through a guide member. The guide frame has a guide member support portion and leg portions defining a recess for receiving the upper portion of the glass panel. The glass panel is inserted in the recess of the guide frame through a packing and the glass panel and the guide frame are fastened by a plurality of through-bolts. Therefore, the glass panel and packing have many notch portions for allowing the bolts to pass therethrough, and the guide member has a plurality of through-holes at the leg portions.
This balustrade involves the following problems yet to be solved. Namely, unexpected external force acts upon the handrail upper side portion to separate the glass panel from the guide frame. Therefore, a large number of screws must be used to cope with this external force. This force is caused by unintentional movement of passengers. Use of such a larger number of screws will increase the assembly cost and labor necessary for maintenance and inspection. Other external force is caused by inversion of the direction of the handrail and acts on the screw portions where the handrail inverts. This force further increases the number of screws. The notch portions of the glass panel are likely to come into contact with the metal screws, and the glass panel may be broken eventually.